New coloring matters



s PATENT OFF ICE" NEW COLORING MATTERS Maurice Arthur Thorold Rogers; Blackley, Mani chestenEnglantl, assignor to Imperial Chemif cal Industries Limited, a corporation of Great a 1 Britain NoDrawlng; Application September s,1942,serial No. 457,228.- In Great Br itain December l 13 Claims. (o1. 260 9240) The present invention relates to' th'e manufac ture of 'new-coloring-matters.-

These new coloring matters" are members of a new class'of colored organic compounds; the simplest member of whichhasthe formula C'zzHzsNs.

I have found that this colored compound CazHzsNe has the constitutional formula here shown;

I have named this compound 2:2:4:4'-'tetra'-' phenyl-aza-dipyrromethine" and the class "2 2" 2 4 4' tetraaryl-s 5' -aza-d.ipyrromethin is. The new class of'fcompounds'has the constitutional formula: i v

R O-- -G -R BV-G:CR

where R R R and R each standcfor an aryl radicahfor example a radical of the benzene or naphthalene series, substituted or not, the same .or different, and where R and R each stand molecular proportion of a 2i4 diarylpyrrole. The 4 interaction may be brought about, for example, by heating the reactants together-advantageously dissolved in a mutual solvent, and preferably in the presence of anacidic condensing agent, for example, acetic acid or acetic anhydride;

Alternatively a 5-nitroso -2;4-diarylpyrrole or its hydrochloride is heated to about 190 C. If a free 5-nitroso-2:4-diarylpyrrole be'used, it is preferable to carry out the heating in presence of a small proportion of an acid.

Again; a 5 amino-2t4-diary1pyrrole is submitted to'the action of an oxidising agent, even a m'ildoxidising agent; e. -g. atmospheric ogygen.

2:4-di'arylpyrroles useful for these embodimen-ts of the invention are compounds of the formula RITI." .C C RXI a 2L; NE- i a where R and: RF each stand Lior'an \aryl radical for example of the benzene or naphthalene series, substituted or not, the same or-difierent,e. g., phenyl, p-methoxyphenyl, p-dimethylaminophenyl, m-nitrophenyL o-chlor0pheny1, m-hydroxyphenyL' pacetylaminophenyl and naphthyl', V

where R stands for hydrogen or for a nonreactive substituentwhich may be, like R and R, an aryl radical, but also may be an alkylor alkylaminoor benzylideneaminoor 'acylaminoradical, and where, as required,X stands for hydrogen or for a nitrosoor an amino radical,

Suitable 2:4-diarylpyrroles' include 2:4-diphenylpyrrole, 2-phenyl-4- (p-methox-yphenyl) pyrro'le, 2(p-methoxypheny1) 1 4 phenylpyrrole, Z-(m-h'ydroxyphenyhe 4 -j phenylpyrrole, 2 -(ochlorophenyl) -4-ph'enylpyrrole,' 2-(p-acety1aminophenyl) 4- phenylpyrrole; v i 2 -naphthy1-4e phenylpyrrole; 2 phenyl-4- p -naphthy1pyrrole, 2 5 3 4-triphenylpyrrole, 3-benzoy1amino -2 :4- diphenylpyrrole, 3 -acety1amino-2 :4-dipheny1pyr: role; 3-benzoylamino -2i 4-di-p.-t0lylpyrrole and 3-acetoacetylamino 5 2A diphenylpyrrole. Also included are the sulphonic acids of the2i4-diarylpyrrolsorsalts ofthese, which may be made, for example, by sulphonating the above compounds; 5-nitroso or 5-amin0 derivatives of these 2 :4-diary1pyrro1esare also included. Mixtures of these compounds may be used.

By way of expl-anationthe formation of the new compounds of this invention is represented in equation formfas'follows itbeing noted that the 2 4-diarylpyrr01es may, by tautomeric interchange, haveeither the formula'A" or B.

uI fi RHI .C=C RII R c be wkhere R R and R have the significance given a ove.

Thus the production of 2-:2'24z4fl-tetraphenylaza-dipyrrometh'ine, C32H23N3, as an illustrative example, is shown in the following equations:

l li -W m -o ONO As yeta further alternative, the new colored compounds are made by a process which comprises heating l-nitromethylor 1-cyano-1:3-diaryl-3-propanones (which may contain a nonreactive substituent in position 2) or simple functional derivatives of these ketones, e, g. their oximes, with ammonia or with an ammonia-yielding reagent, an oxidizing agent being present when necessary, that is when the l-cyano-propanones are being used.

In carrying into efiect these features 'of the invention the l-nitromethylor the 1-cyano-1z3- 'carried out under such conditions that the water is removed from the reacting mass.

The aryl radicals of the above mentioned propanones includethose of the benzene or naphthalene series, substituted or not, the same or difierent, e. g., phenyl, p-methoxyphenyl, p-dimethylaminophenyl, m-nitrophenyl, o-chlorophenyl, m-hydroxyphenyl, p-acetylaminophenyl or naphthyl; the non-reactive substituent in position 2 may be an aryl, a1kyl-, alkylamino-, benzylideneaminoor acylamino-radical. The compounds can be described as generators of 2:4- diarylpyrroles, inso far as they are capable of forming the 2:4-diarylpyrroles used in the hereinbefore described features of the invention, by reactions involving ring formation. The l-nitromethyl-1z3-diaryl-3 propanones may also be described as 1-nitro-2:4-diaryl-4-butanones and the l-cyano-l:3-diaryl-3-propanones may also be described as 1-aryl-Z-aroyl-propionitriles. Suitable 1-nitro-2:4-diaryl-4-butanones include 1-nitro-2 4-diphenyl-butanone-4, 1-nitro-2 4-di- (p-methoxyphenyl) -butanone-4, 1-nitro-2- (pmethoxyphenyl),-4-phenyl-butanone-4, l-nitro- 2-phenyl-4- (p-methoxyphenyl) -butanone-4, 1-

nitrO-Z-(m-nitrophenyl) -4-phenyl butanonei,

l-nitro-2-(m-hydroxyphenyl) 4 phenyl-butanone-4, 1-nitro-2-(p-dimethylaminophenyl) -4- phenyl-butanone-4, 1-nitro-2- (3 i-methylenedioxyphenyl) -4-phenylbutanone-4, or their oximes. Suitable 1-aryl-2-aroyl-propionitriles include 1- phenyl-2-benzoyl-propionitrile, l-(p-methoxyphenyl) 2-benzoylpropionitrile, 1-phenyl-2.-(pmethoxybenzoyl) -propionitrile, 1- (m-hydroxyphenyl) 2 benzoylpropionitrile, l-(o-chlorophenyl) -2-benzoylpropionitrile, 1- (p-acetylaminophenyl)-2-benzoylpropionitrile, lax-naphthyl- 2-benzoylpropionitrile, 1-phenyl-2-p-naphthoylpropionitrile, l-(p-dimethylaminophenyl) -2-ben- 1-nitro-2:4-diphenylbutanone-4 and formamide,

may be illustrated by'the following equation;

When a 1-phenyl-2-benzoyl-propionitrile is used, as illustrated by the following equation, the formation of 2 2 :4 4'-tetraphenyl-aza-dipyrro- The above processes starting with either a nitro-diaryl-butanone or a cyano-diaryl propanone are interrelated and are further closely related to the process which start with an aminodiaryl-pyrrole, as will be apparent from the following'considerations'. I

To begin with, taking formamide for instance, this one has a tendency to decompose into carbon monoxide and ammonia. Therefore, in the case of a nitro-diaryl-butanone, the reaction may be looked upon as proceeding in stages whereby the reducing effect of the CO and simultaneous elimination of water first convert the nitro-butanone toa cyano-propanone. Again, by the action of ammonia on the latter, an amino-pyrrole may be expected as intermediate product. Thus, starting with either the nitro-butanone or the cyanopropanone type of initial-material produces a reaction mass which is equivalent in effect to starting with. an amino-pyrrole.

As shown above, the last-mentionedreaction generally requires the presence'of a mild oxidizing agent. In the nitro-butanoneprocess, the reaction will ofen proceed without an oxidizing agent. This is to be explained by the very probable assumption that the oxygen is furnished by the nitro group.

The new 2:2 :4:4-tetraryl aza dipyrromethines are solids of high melting point. Some will sublime unchanged. Their color is blue, of shade varying according as the phenyl radicals are substituted or not, and according to the nature of the substituents, if any. The differences in shade between these compounds are more pronounced when the compounds are viewed in the crystalline form by reflected light, than when they are viewed in solution by transmitted light. They are sparingly soluble in most organic solvents. They do not readily react with most simple reagents, unless reactive groups,,e.; g., salt forming groups, are present, for instance, as substituents in the phenyl radicals.

The new compounds'may be used as pigments and for other coloring purposes, and it is a feature of the inve'ntion to use products when prepared ashereinbefore described or by the obvious chemical equivalents of these processes for coloring purposes, especially in relation to textiles, and in the production of coating compositions. In the form of their water-soluble derivatives, for example, salts, or sulphonic acids or salts of these, the new coloring matters are especially useful for dyeing textiles. The water-soluble derivatives may be obtained by forming salts of those of the coloring matters which are sufiiciently basic, for example withsulphamic acid, by forming quaternary ammonium-salts (when quaternary salt-forming groups are present), for example with methyl iodide, or by sulphonation of the coloring matters to yield sulphonic acid derivatives which are in themselves, or in the form of their salts, soluble in water. Alternatively, the sulphonic acid derivatives may be obtained by using the initial reagent, or one or more reagents: where more'than one initial reagentis mecca used, in the form of a sulphonic acid derivative or a salt thereof. The-synthesis of these is described more fully and claimed in my copending appli cation Serial No. 482.479, which isto beis'sue dine.

14 3 further purified m "recrystallisation; from pyri- The following table lists in the thirdcolumn the aza-dipyrromethiii'es which are made by the those of high boiling point. ,I'hus from hot- 2;

ethoxy-ethy1 alcohol (Cellosolvef--registered trade'-mark), or from hot nitrobenzene or from dioxan, it forms clusteredneedles, dark blue in color with a metallic-coppery-re'flex.'

It dissolves in cold concentrated sulphuric acid to give a deep blue solution, which on immediate dilution Wi'thwater givesablue precipitate. l

dersubatmosphericpressureitjjsublimes 1 "EXAMPLIZ 52 parts of"l nltro m-dflp-metho hefiyiie butanone i (made by condensin'g'pm di-methox cheikone with nitromethane) "are heated wlth 160 pertsorammonium 'formate to 1811 "C; a

molten mass is not homogeneous, and part blue incolor. when the blue oil first formed solidifies-to crystalline paste andm further coloring matter appears to be being formedfthe reaction 'mass is cooled; and mixed with 250 parts of ethyl alcohol, the crystalline blue material being almost insoluble in'alcohol. It is ,then filtered off, washed with ethyl alcohol and diied. There is. thus obtained 2 2" :4: 4-tetra (memeth oxyphenyl) -aza"-dipyrromethine, which i may 1 be 2t bfYB nitroso ri diphenylpyrrole hfye drochloride (made by treatment of 2':4-diphenyl-pyrrole with sodium nitrite and hydrovchloriciacl'cl; seepf-or instance; Example 1 of my copendl ngr appli'catlon-Ser; No. 457,230), and 22 parts of 2:4 d1pheri'y1pyrro1e are dissolved in 100 parts of gl'acial"acetid acid. Theyellow solution f is heateuto boilin'g in a vessel provided with a reflux-condenser: It repialy' becomes deep blue in co or and crystals of a blue compound separate. When the reaction is complete as Judged by there being no indication of continued formation of blue compound the mixture is filtered.

- "product is ldentlcabwith that or E1;-

Instead "of 22 parts of 2:4-diphenylpyrro1e there'maybe'usedfi parts of 2-phenyl-4 p methoxwphenwpyrromfend there is thus ob; tained :4 -trip "enyl- 4"-'p methoxyphenyl- 4 parts or 5-nltioso-=2 ee oipn'enyipmole hydrochloride and 6 or 3-benzoy1'amino-2 :4I-diphenylpyrrolearedlssolvedin 250 parts of acetic anhydrioe. Thesolution isheated to boiling for about h'our'in a vessel provided with a reflux condenser. It rapidly-turns deep'blu'e; The blue 1 solution is poured into 500"p'arts of cold water,

and. the aqueous :mixture is stirred until the acetic anhydrideqhasbecome converted into acetic:-acid.j1t isthen filtered. The blue solid .75.

obtainedll-iswashed with" water and dried.

2:4-diphenylpyrrole with hydrogen in methyl alcohol solution in the presence of a platinum oxide catalyst. The -amino-2 :4 diphenylpyrrole so obtained is soluble in hot benzene, from which it separates on cooling in the form of colorless needles, M. P. 155156 C."

ExAMPLnG 1 party of 1-a-naphthyl-2-benzoylpropionitrile (M. P. 84 0., prepared by'addition of hydrogen I cyanide to the chalkone formed by condensation f heated to 180 C. with 5 parts ammonium f'ormate in the presence of air.- The molten mass is not homogeneous and the oil becomes" blue in color and finally, solidifies. v cooled, mixed with parts of methyl alcohol and the sparingly solubleblue material; 2:2-

diphenyl 4:4 di 05-. naphthyl aza dipyrromethine, is filtered off and dried.

ExAMP z: '7 1-phenyl-2-p-naphthoylpropionitrile (M; P.

124 0., made by addition of ,hydrogencyanide to the chalkone, M. P. 106 0., obtained by 'condensing benzaldehyde with s-acetonaphthone) is treated with ammonium formate-under the conditions described in iExampleG and there is thus obtained 4 :4 -diphenyl-2 :2'-di-fi-naphthylazadipyrromethine.

EXAMPLE 8 1-a-naphthyl-2-13-naphthoylpropionitrile, (M. P. 142 C. made by addition of hydrogencyanide to the chalkone, M. P. 161 0., obtained bycondensing u-naphthaldehyde with fi-acetonaphthone) is treated with ammonium formate under the conditions described in Example 6' and-there is thus obtained 2:2'-di-p-naphthyl-4Wadi-a naphthyl-azadipyrromethine. I

' j EXAMPLE 9 2'7 parts'of 2-phenyl-4-aenaphthylpyrrole and 28 partsv of 5-nitroso-diphenylpyrrole are dissolved together in a mixture of 100 parts of glacial acetic acid and 10 parts of acetic anhydride and the solution is heated to boilingunder a reflux condenser. The solution soonbecomes a deep reddish-blue in-color and later blue crystals separate. When no furtherlblue crystals separate the mixture is cooled and filtered and the insoluble 2 :2 :4-triphenyl 4 a-naphthyl-aza-dipyrrolmethine is washed and dried. I i

,The 2-phenyl 4-u-naphthylpyrrole used in this example is obtained by dehydrogenating, by means of selenium (see, forinstance, Example 1 of my copending application vSer..No.- 457,229), thepyrrolineobtained by hydrogenation of l-anaphthyl-Z-benzoylpropionitrile. v

EXAMPLE 10 I 125 parts of 5-nitroso-2:4 diphenylpyrrole and 110 parts of 2:4-diphenylpyrroleare heated to 100 C. with 250 parts of acetic acid and 50 parts The' reaction massds a-naphthaldehyde. with acetophenone) is of acetic anhydride for 30uminutes. The blue cry's'talswhich form are separated by filtration, Washed and'dried. 215 parts are obtained. The product isidentical with that of Example 1.

EXAMPLE 11 -1 part of l-nitro-Z:4-diphenyl-butanone-4 is heated with 5 parts of aqueous ammonia (Sp. Gr, 0.88) in a closed vessel at 180 C. for 12 hours. The vessel is cooled, opened, and the liquid, containing the "excess. of aqueous ammonia, is decanted from the tarry deposit. which has formed.

-'-I'he tarry deposit is mixed with ethyl alcohol,

and the 2 :2 :4 :4-tetraphenyl-aza-dipyrromethine, now in the form of a blue finely crystalline mass, is collected by filtration, washed and dried.

EXAMPLE 12 16 parts of finely powdered sodium 2:4-diphenylpyrrole mono-sulphonate (made by sulphonating the pyrrole under conditions such that a mono-sulphonic acid is formed, and then converting'the product to the sodium salt; see for instance Example 1 of my copending application Serial No. 482,479), 14 parts of 5-nitroso-2z4-diphenylpyrrole hydrochloride, 100 parts .of acetic acid and 10 parts of acetic anhydride are heated together to boiling for 2-hours. After cooling, the blue solid, which has separated, is removed by filtration, washed and dried. -It is 2:2:4:4- tetraphenyl-aza-dipyrromethine mono-sulphonic acid. 20 parts are obtained. The new product is slightly soluble in water or in dilute aqueous sodium hydroxide, and is more soluble in dilute aqueous pyridine. I

EXAMPLE 13 3.8 parts of 2:4-diphenylpyrrole disulphonic acid (made by sulphonating the pyrrole under conditions'such that a disulph'onic acid is formed; see 'for instance Example 2 of my copending application'Serial No. 482,479), 2.4 parts of 5-nitroso-2:4-diphenylpyrrole, 100 parts of acetic acid and 20 parts of acetic anhydride are heated to the boil for about 1 minute, cooled and the so-formed black tar is Washed with acetic acid, It is 2:2: 4 4-tetraphenyl-aza-dipyrromethine disulphonic acid, and is soluble in water forming strongly blue colored solutions; which dye Wool in blue shades fr'oman acid dye-bath. '1 In place of the 5 nitroso-2:4-diphenylpyrrole there "maybe used 5'-nitroso-2-(p-methoxyphenyl) -4-'phenylpyrrole.

EXAMPLE 14 3 parts of finely powdered 5-nitroso-2:4-di phenylpyrrole monosulphonic acid) made by nitrosating 2:4-diphenylpyrrole monosulphonic acid; see for instance Example 2 of my copending application Serial No. 457,230) 3 parts of finely powdered ,sodium 2 4-diphenylpyrrole monosulphonate,. 400 parts of acetic acid and parts of acetic anhydride are heated together to boiling 0112 hours. .After cooling,v the blue precipitate, which has formed, is removed by filtration, washedand dried It is 2:2: 4:4'-tetraphenyl-azadipyrrom ethine disulphonic acid, and is isomeric with the product of Example 13, difiering in that it is less soluble in water or dilute alkalies.

I EXAMPLE 15 c 1 The 'following'example gives another method of converting a tetraaryl-aza-dipyrromethine into a water-soluble derivative: v

22' diphenyl 414' di(p dimethylaminophenyl)eaza dipyrromethine, made according to the method of Example 2 is mixed with 2 molecular proportions of methyl iodide dissolved in nitromembers represented by the formula hereinbelow and the salts and addition compounds of such members, said formula being wherein RER R and R stand each for an aryl radical having not more than 10 carbon atoms in its nuclear structure, and wherein R and R stand for members of the group consisting of hydrogen, alkyl, alkylamino, benzylideneamino,

acylamino and aryl of not more than 10 cyclic carbon atoms.

3. Water-soluble quaternary ammonium salts of the compounds having the formula set forth in claim 2.

4. The water-soluble reaction product of su1famic acid upon a compound of the formula as defined in claim 2.

. 5. A compound as defined in claim 2, wherein at least one of the aryl radicals represented by R R R and R carries a sulfo group.

'6. A compound as defined in claim 2, wherein;

the aryl radicals represented by R R R and R, are benzenoid radicals at least one of which carries a sulfo group. it

the sulfamicacid addition compounds of the same, sulfonic acid derivatives of the same and salts of the latter, and in which the aryl radicals specifled possess no more than 10 cyclic carbon atoms each. t

8. A compound selected from the group consisting of the free base form and quaternary ainmonium derivatives of a compound of the formula wherein R R R and R each stands for a benzenoid aryl radical.

9.'Process for the manufacture of coloring compounds which comprises heating a member of the group consisting of 2:4-diary1-5-aminopyrrols and initial materials adapted to yield 2:4-diaryl-5 amino-pyrrols in situ, in the presence of an oxidizing agent, to effect condensation between two molecules of said compound with formation of a 2:2i:4:4'-tetraaryl-5:5'-aza-dipyrromethine as expressed by the formula Q-N=Q, wherein Q and Q are. respectively monovalent and divalent radicals of 2:4-diarylpyrrols attached to the N-atom above shown in their respective 5-position.-

10. A process as in claim 9, the initial material being a mixture of ,a 1-cyano-lz3-diaryl-3-propanone and an ammonia yielding agent. I

l 1. A process as in claim 9, the initial material being a mixture of a 1-nitro-2:4-diaryl-4-butanone and an ammonia yielding agent.

12. Process for the manufacture of coloring compounds which comprises reacting a 2:4-diaryl-5-nitroso-pyrrole with a 2:4-diaryl-pyrrole ,having a free 5-positi0n, in the presence of acid,

'7. A compound of theseries consisting of the free base form of 2:2:4:4-tetraaryl-5:5'-azadipyrromethines, quaternary salts of the. same,

to yield a 224:2:4-tetraaryl-5:5'-aza-dipyrromethine.

13. Process for the manufacture of coloring compounds which comprises heating a 2:4-diaryI-B-nitroso-pyrrole in the presence of acid to yield a 2:4:2'.:4'-tetraaryl-5:5'-aza-dipyrromethine.

MAURICE ARTHUR THOROLD ROGERS.

CERTIFICATE OF CORRECTION.

August 11+, 19L 5.

Patent No 2,582, 91L! MAURICE ARTHUR THOROLD ROGERS.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows Page 5 in the table third column thereof, seventh compound, for "2:2:14. :LIJ -tetra'" read 2:2 :LpzLu-tetrapage h, first column, line 6h, Example 9, for "pyrrolmethine" read pyrromethine; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 15th day of November, A. D. 19L 5.

Leslie Frazer (Seal) First Assistant Commissioner of Patents 

